Implantable devices such as implantable defibrillators can be beneficially used to automatically detect malignant arrhythmias in patient cardiac function and deliver appropriate therapy. There are known indicators for determining whether a patient is susceptible to arrhythmias, and whether the patient is therefore likely to benefit from receiving an implantable cardiac stimulation device. For example, measurements of ejection fraction coupled with patient history can be used to determine whether a patient may benefit from implantation of an implantable cardiac stimulus device (ICSD). Having identified a patient who needs an ICSD, the next step is to determine which of several ICSD options best suits the patient's needs. Tools for identifying patients who are well suited to certain ICSDs are desired. Additional alternatives and options are desired.